<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
        <meta http-equiv="X-UA-Compatible" content="ie=edge"/>
        <title>Document</title>
        <style>
            *{margin: 0px; padding: 0px}
            #div1{width: 200px; height: 200px; background-color: red; position: relative; display: none}
            #div2{width: 50px; height: 50px; background-color: yellow; position: absolute; right: 0px; bottom: 0px}
            #div3{width: 100px; height: 100px; background-color: blue; position: absolute; right: 0px; top: 0px}
        </style>
        <!-- 
            defer IE兼容的异步加载js文件
            data-main = "入口文件"

         -->
        <script src = 'js/require.js' async = 'true' defer data-main = "js/xxx"></script>
    </head>
    <body>
        <button id = 'btn1'>显示控件</button>
        <div id = 'div1'>
            <div id = 'div2'></div>
        </div>
        <div id = 'div3'></div>
    </body>
</html>